MgAl hydrotalcites (Mg/Al molar ratios 3 and 4) were synthesized using alkali and alkali-free methods at different pH's. They were calcined to form MgAl oxides, and then loaded with Na, K metals at different content. The characterization was performed with XRD, BET, and FTIR techniques, and the basicity was determined using the Hammett titration method. The oxides prepared using the alkali method gave higher soluble basicity than ones using the alkali-free method. Glyceryl tributyrate was used as a model compound for vegetable oil to study transesterification. with methanol catalyzed by the metal-loaded MgAl oxides. The results showed that the catalysts synthesized with a Mg/Al molar ratio of 4 and at pH 11 are more basic than those with a ratio of 3 and at pH 8, due to higher incorporation of Mg in the oxides, resulting in higher catalytic activity. For the metal-loaded catalysts, under the same reaction conditions, it was found that the MgAl oxide loaded with 1.5% K gave the highest activity. It was therefore used for the biodiesel synthesis from palm oil. The ester content and yield of biodiesel were 96% and 87% at temperature 100 degrees C in 9 h. The catalyst could be regenerated by recalcination and reloading metal.